Shaft packing



.May 26, 1942. o. WOOD, JR I SHAFT PACKING Filed NOV. 25, 1940 ,2Sheets-Sheet l Lnvenbor. OPla'L.Wood,Jn, by War/1 6M His Attorney.

O. L.-WOOD, JR

May 26, 1942.

' SHAFT PACKING Filed Nov. 25, 1940 2 She ets-Sheet 2 Fig.2..

4 lillllllll I a b Z In HIS Attofney.

Patented May 26, 1942 SHAFT PACKING Orla L. Wood, Jr., Schenectady, N.Y., assignor to General Electric Company, .a corporation of New Yorl:

Application November 25, 1940, serial No. 367,078

15 Claims.

The present invention'relates to shaft packlugs to reduce leakagebetween a shaft or like rotatable element and a casing or likestationary element. More specifically, the invention relates to packingsin which the seal is efiected by a liquid of the general type disclosedin the Patent No; 2,133,879, issued October 18, 1938, to E. L. Thearleand assigned to the same assignee as the present application.

In packings of this kind a vane or like element projects into a grooveformed by a rin or cup element. Liquid is continuously supplied to thegroove and forced along the groove during rotation of a horizontal shaftto which one of the elements is secured. Such packings effect a completeseal as'long as the shaft is rotated,

and a turbine rotor having a shaft llprojecting through the opening andsupported on a bearing l2.j-.. The casing portion shown in the drawingis at the exhaust or vacuum end. The packing for sealing the shaft tothe turbine 'casinB to prevent leakage of air from the atmosphere intothe turbine comprises a ring i3 securedto an end flange oi the casingllby a plurality of bolts 14. 'A runner or rotatable packing element forexample, in case the packing forms part of a turbine the turbine shaftis sealed to the turbine casing during operation of the turbine. Incertain instances, such as in the case of mercury turbines, it isdesirable to seal the shaft to the casing also during standstill oi theturbine inorder to prevent leakage of air. from the atmosphere into theturbine which upon subsequent operation would eflect undesirableoxidation of the mercury.

I5 is secured to the shaft H and forms a vane I5; Two axially spacedcast ironpacking rings i1 and I8 have a minimum running clearance,

that is sealing engagement with'the runner it are biased axially towardsthe ring l3 and a shoulder 19 formed by the casing Hi. To this end rings20 and 2| are riveted to the sealing rings l1 and i8 respectively andbiased in opposite directions by means including a plurality oi.circumferentially spaced springs 22 engaging and suitably supported onopposite sides or the rings 20 and 21'. Thus, the ring iT-is biased intoThe object of my invention is to provide an im- 1 proved packingarrangement whereby a horizontally disposed shaft or like rotatableelement may be effectively sealed to a casing during standstill of theshaft or stationary element as well as while the shaft is rotated. Thisis accomplished in accordance with my invention by the provision ofmeans forming a liquid seal between an element secured to the shaft anda normally stationary element rotatably supported on the casing and theprovision of other means for rotating the second element upon standstillof the shaft. The means for rotating the other element may be anysuitable power agency such as an elastic fluid turbine wheel to whichsuch other element is secured or an electric motor.

For a better understanding .0! what I believe to be novel and myinvention, attention is directed to the following description and theclaims appended thereto in connection with the accom- 1 panyingdrawings.

In the drawings Fig. 1 illustrates anelastic fluid turbine arrangementembodying my invention; Fig. 2 shows a modification in accordance withmy invention; and Fig. 3 is a section along line 3-4 M Fig. 2.

vapor having a casing Io .iorming an opening sealing engagement with thering it and the ring I! is biased into sealing engagement with theshoulder I! to reduce leakage along the runner.

One part of the liquid sealing meaiis is formed by the runner IS withthe vane I6 and the other part of the liquid sealingmeans comprisesaring or cup element 23 forming a groove 24 into which the vane l6projects. The ring or cup element 23 according to my invention isrotatably sup- 7 ported. In the present example, th element 23 issecured to an auxiliary turbine wheel 25 by means 01' a plurality ofbolts 25. The turbine wheel in turn is supported on a packing casing 2!through the intermediary of a bearing 28 held in position on the packingcasing by a ring 29 secured to the packing casing by bolts 30. The

packing casing 21 has an outer portion 31 which forms an exhaust chamber32 with an outlet 33 for receiving iiuid exhausted from the turbinewheel 25. Operating fluid which may be mercury vapor or compressed airin case of a mercury vapor turbine is conducted to-the .turbine wheel 25by an inlet conduit 34 and a plurality of nozzle passages 35 formed inthe packing casing 2'3. The exhaust casing it which also constitutespart of the packing casing is secured to the main turbine casing 10 byaplurality of bolts 38 and the packing casing 21 is also supported on aring it by bolts 38. The ring 31 in turn is held on the bearing l2 bybolts 39. The stationary part of the liquid seal also includes a vane 40formed by a lateral extension or projection of the ring l3 and havingend portions located within the groove 24 of the ring or cup element 23.Liquid such as mercury'is continuously conducted to the groove 24 from asource, in the present instance indicated as a tank 4|, for containingmercury 42. The mercury liquid is forced from the tank 4| to the groove24 through a conduit 43 connected to a channel 44 in the turbine casingIII, which channel communicates with another channel 45 through the ringI 3 and the vane 48. A cooling element 46 is disposed within the tank 4|for cooling the mercury therein. The fiowvof mercury from the tank tothe sealing groove may be effected by the supply of gas, such asnitrogen under pressure, to the vapor space in the tank 4| by meansincluding a valved conduit 41.

During operation, mercury is continuously conducted to thegroove 24 andforced around or along the groove to effect a complete liquid sealbetween the'vanes l6 and 48 on one hand and the ring 28 on the otherhand by rotation of the shaft or the turbine wheel 25. While bothelements may be rotated at the same time, it is more economical tomaintain the ring 23 at rest during rotation of the shaft. Uponstandstill of theshaft, that is, when the turbine is shut down, however,the ring 28 is rotated by conducting operating fluid through the conduit34 to the turbine wheel 25.to effect rotation of the latter and of thering 23. Mercury-liquid discharged from the groove 24 over the righthandend of the ring 23 is returned to the tank 4| through a channel 48formed in the casing 3| and a valved conduit 48 connecting the channel48 to the tank 4|. Likewise, mercury liquid discharged from the lefthandside of the groove 24 is returned to the tank 4| through a plurality ofchannels 58 partly formed in the ring 28 and partly in the bucket wheel25. The sealing liquid is discharged from the channels 58 into anannular groove which communicates at its lower end with a channel52formed in the casing 2'land connected by a conduit 53 to'theaforementioned return conduit 49.

The modification according to my invention as shown in Figs. 2'and 3comprises a mercury turbine having a rotatable member'or rotor with ashaft 55 and a last stage bucket wheel 56 enclosed by a turbine casing51 having an opening 58 through which the shaft 55 projects. The packingarrangement for sealing the shaft 56 to the casing 51 includes 'alabyrinth type packing 59 having a casing 68 supported on the turtherebyforming a liquid seal between the interior of the turbine and theatmosphere. The ring or runner 64 is arranged in cooperative relationwith another packing element in the form of a ring H concentricallyarranged with and spaced from the shaft 55 and the ring 64. The ring Hhas a lateral projection 12 forming an inner annular groove 13 facingthe shaft. The aforementioned vane 66 of the ring 64 and another vane orannular projection 14 formed on the casing end portion 68 project intothegroove 13. The righthand end wall of the projection I2 isconcentrically arranged with and projects into a groove 13a of thecasing end portion 68.

During rotation of the shaft 55 and the runner 54, sealing liquid, inthe present instance mer cury, is discharged from-the groove 65 into thegroove 13. Rotation of the runner 64 forces the liquid along the groove13 to form a second liquid seal between the vanes 66 and 14 in groove13. Thus, during operation of the turbine, two liquid seals arranged inseries as regards the flow of leakage are formed to prevent leakagebetween the interior of the turbine and the atmosphere,

- one liquid seal being formed between the runner 64 and the vane 61 inthe groove 65 and the other liquid seal being formed between the vane 56of the runner 84 and the vane 14 of the casing end portion 68 and theprojection 12 of the ring 1|.

During operation, mercury liquid flowing from the first sealing groove65 into the second sealing groove i3 is discharged from the latter intobine casing 51 by means of a ring 6| and a plushaft bearing (not shown)from entering the packing. The latter in addition includes a liquid sealtype packing arrangement formed by means including a ring or runner 64secured to the shaft 55 and forming an inner annular groove 65 and anouter projection or vane 66. The groove 65 is arranged to cooperate witha vane 61 projecting into the groove and formed on an end portion 68 ofthe casing 51. Sealing liquid such as mercury is conducted to the groove65 of the ring or runner 64 through a conduit 89 connected to a channell8 formed in the casing end portion 68.

During operation of the turbine, rotation of the shaft 55 and the runner64 forces the mercury liquid supplied to the lower portion of the groove65 along this groove to form a liquid an annular chamber or groove -15vformed by the casing end portion 68 and a ring 16 secured to the casingend portion 68 by a plurality of bolts H. Mercury is drained from thechamber 15 through a drain channel 18 formed in the lower part of thecasing end portion 68. The opening ,58 of the turbine casing forms anannular groove 19 on the vacuum side of the packing from which leakageof mercury is discharged through if a drain channel 88 communicatingwith a lower.

portion of the groove 19.

In order to reduce leakage between the annular chamber l5 and theatmosphere, a sealing chamber 8| is formed by a projection 82 of thering 76. Two carbon packing rings 83 and 84 are disposed within thechamber 8| and axially biased away from each other into sealingengagement with the projection 82 and the ring' 16 by means of aplurality of springs 85 between the rings 83, 84 to prevent leakage ofmercury vapor from the chamber 15 and of air from the atmosphere intothe chamber 8|. The chamber is filled with a gas at a pressure slightlyabove that of the atmosphere. Non-oxidizing gas, such as nitrogen, isconducted to the chamber by means of a conduit 86. With this arrangementnitrogen or similar sealing gas flows from the chamber 8| along thepacking ring 84 into the chamber 15 and along the packing ring 83 intothe atmosphere. A similar sealing arrangement is formed between the ringH and the shaft 55. The shaft is surrounded by a ring 81 supported onthe packing casing 80 by means including a plurality of bolts 88 andforming a packing chamber 88. Two carbon type packing rings and iii aredisposed within the chamber 89 and biased apart by means of a pluralityof springs 92 engaging adjacent sides of the rings. Packing ring 90 hassealing engagement withthe shaft 55 and is biased towards the lefthandwall of the chamber 88 while-thering 8| has sealing engagement with aprojection as and the ring ii and is biased towards the righ'thand wallof the chamber 89. Gas, such as nitrogen, is conducted to the chamber itby means of a conduit to at a pressure slightly above that of theatmosphere. During operation, sealing gas flows along the inner sealingsurface of the ring 90 towards atmosphere, thus preventing air fromentering the chamber ll, and sealing gas also flow! along the innersealing surface of the ring SI towards the atmosphere, thus preventingleakage of air through the chamber It to the sealing groove ll.

In order to permit sealing of the turbine casing to the shaft while theturbine is out of operation, that is, during standstill of the turbine.shaft, means are provided for rotatably supporting and'rotating theringII. "The supporting means includes four pairs of rollers It, It, 81

and 88 which broadly constitute a roller bearing. The lower rollers 95and 90 have shafts supported on brackets 98 secured to the packingcasing 60 by bolts I". The upper pairs of rollers 81 and 98 aresupported on a common bracket IIiI held on the packing casing Bil bybolts I02.

Whereas in the arrangement of'Fig, l the ring or cup element 23 isdriven by an auxiliary-turbine, in the present arrangement thecorresponding ring element II is driven by an electric motor through agearing. To this end the ring II is 'provided with a beveled gear I03inte rally formed with the ring and meshing with another beveled gearlfll'secured to a shaft I. The shaft I05 is supported by a bearing I06held on the aforementioned bracket III. The shaft projects through achannel member IIil' passing through and fused to the exhaust end of theturbine casing 51. The shaft is driven at its upper end by an electricmotor I08.

As the turbine is put out of operation the motor Hi8 is started toeffect rotation of the ring II. with the ring 84 at rest, mercurysupplied to the lower end of the groove 65 flows over into the groove I3formed by the projection I2 of the ring 1 I. Rotation of the ring llforces the mercury along the groove '13 to eifect a liquid seal betweenthe projection I2 and the vanes 81 and '14. Mercury is discharged fromthe groove 13' into the annular chamber I5, whence it is drained throughthe channel I8, as described'above.

Thus, with the present arrangement a single liquid seal is formed uponrotation of the ring II during standstill of the shaft 55, whereas adouble seal is formed .during rotation of the shaft Having described themethod of operation of my invention, together with the apparatus which Inow consider to represent the best embodiment thereof, I desire to haveit understood that the 2. The combination of a rotary shaft member,

a stationary turbine casing member having an opening through which therotary member proiects, a first element secured to such rotary member, asecond element concentrically arranged with the first element, means forrotatably supp r ing the second element, means for rotating the secondelement, one of the elements forming an annular groove, the otherelement having a vane projecting intothe groove, and, means forconducting sealing liquid to the groove to form a liquid seal betweenthe two elements during rotation of either of them.)

3,-Packing arrangement for sealing a turbine casing having an openingand a rotary shaft member projecting through the opening comprising afirst and a second element, means for rigidly securing the first elementto the shaft, means for rotatably supporting the second element on suchcasing, means for rotating the second element, one of the elementsforming a groove facing the shaft, the other element having a vaneconcentrically arranged with and proiecting into the groove, and meansfor conducting sealing liquid to the groove to form an annular sealbetween the two elements during rotation of either of them.

4. Packing arrangement for sealing a turbine casing having an openingand a rotary shaft member projecting through the opening comprising afirst and a second element, means for rigidly securing the first elementto the shaft, means for rotatably supporting the second element on suchcasing, means for rotating the second element, one of the elementsforming a groove facing the shaft, the other element having a vaneconcentrically arranged with and projecting into the groove, meansfastened to the casing and forming another vane projecting into thegroove, and means for conducting sealing liquid to the groove to form anannular seal between the two elements during rotation of either of them.

5. The combination of a turbine casing having an opening, a rotatableshaft member projecting through the opening, a first and a secondelewith each other, one ofthe elements forming a apparatus shown is onlyillustrative and that the invention may be carried out by other means.What I claim as new and desire to secure by LettersPatent of the UnitedStates is:

l. The combination with a turbine casing havelement, and means'forconducting liquid to the groove to effect a liquid seal between the twoelements during rotation of either of them.

groove, the other element forming a vane proiecting into the groove,means for rigidly secur-' in! the first element to such rotatablemember. means for conductingsealing liquid to the groove whereby aliquid seal is formed between the two elements during rotation of therotatable member, and means for rotating the second element to form aliquid seal between the two elements while the rotatable member is atrest.

6. The combination with a turbine casing having an opening andashaftprojecting' through the opening, of a packing arrangement forsealing the shaft to the casing comprising a firstand a second elementconcentrically arranged with the shaft, one of the elements forming anannular groove, the other element having a vane projecting into thegroove, means rigidly securing one of the elements to the shaft, andmeans for rotatably supporting and rotating the other element comprisingan auxiliary turbine wheel secured to the other element and a bearingfor rotatably supporting the turbine wheel.

shaft is at rest, said packing arrangement com prising an elementforming an annular groove concentrically spaced from and facing theshaft, a runner fastened to the shaft and having a vane projecting intothe groove, a ring secured to the casing and having a vane adjacent theother vane and projecting into the groove, means for conducting sealingliquid to the groove whereby a liquid seal is formed between the vanesand the element during rotation of the shaft, and means for rotating theelement to form a liquid seal between it and the vaneswhile'the shaft isat rest.

8. The combination with a turbine casing having an opening and a shaftprojecting through the opening, of a packing arrangement for sealing theshaft to the casing during rotation of the shaft as well as while theshaft is at rest, said packing arrangement comprising a rotatableelement forming an annular groove concentrical- 1y spaced from andfacing the shaft, a runner fastened to the shaft and having a first vaneprojecting into the groove, a ring secured to the casing and having asecond vane adjacent the first vane projecting into the groove, meansincluding a channel through the second vane for conducting sealingliquid [to the groove to form a liquid seal between the vanes and theelement during rotation of the shaft, and means includ ing a motor forrotating the element to form a liquid seal between the element and thevanes while the shaft is atrest. v

' 9. The combinationwith a main mercury turbine having a casing with anopening and a horizontally disposed shaft projecting through theopening, of a packing arrangement for sealing the shaft to the casingboth during operation and shutdown periods, said packing arrangementcomprising a runner with a vane secured to the shaft, another vanesecured to the casing, an element having a groove concentrically spacedwith and facing the shaft, said vanes projecting into the groove, meansfor conducting mercury liquid to the groove to form a liquid sealbetween the vanes and the element during rotation of the shaft, and anauxiliary elastic fluid turbine including a bucket wheel supporting theelement,

to the shaft, a second element cooperatively arranged with the firstelement, one of the elements forming a groove facing the shaft, theother element having a vane projecting into the groove, means forconducting sealing liquid to the groove, means rotatably' supporting thesecond element, and means including a motor driven gearing for rotatingthe second element while the shaft is at rest.

11. The combination with a turbine casing having an opening and a shaftprojecting through ing the shaft to the casing, said packing arrangementcomprising a runner securedto the shaft and having a vane, an elementconcen trically surrounding the shaft and forming a groove for'receivingthe vane, means for conducting sealing liquid to the groove, means in=--eluding a plurality of rollers supporting the ole-- ment, and meansincluding a motor driven gearing for rotating the element while theshaft is at rest.

12. The combination with a turbine casing having an opening and a shaftprojecting through the opening, of a packing arrangement for seal ingthe shaft to the casing, said packing ar rangement comprising a runnersecured to the shaft, a member fastened to the casing and forum ing agroove facing away from the shaft, avane opening and a shaft projectingthrough the opening, of a packing arrangement for sealing the shafttothe casing, said packing arrangement comprising a runner secured tothe shaft, a member fastened'to the casing and forming a groove facingaway. from the shaft, a vane on said runner projecting into said groove,an element concentrically spaced with the shaft and forming a groovefacing the shaft, another vane formed on the runner projecting into thelast mentioned groove, means for conducting sealing liquid to saidgrooves to form liquid seals between the vanes, said member and saidelement, and means forrotating said element while the shaft is at resttoform a liquid seal between the runner and said element, said last namedmeans comprising a plurality of pairs of rollers supported on the casingfor rotatably supporting the element and a motor driven gearingincluding a gear formed on saidelement.

- the opening, of a packing arrangement for seal- 14. The combinationwith a stationary turbin casing havingan opening and a rotatable shaft.member horizontally disposed and projecting through the opening, of arotary liquid sealing arrangement for sealing the rotatable member tothe casing while the rotatable member is at rest, said arrangementincluding a ring having an inner groove, means sealing the ring to thecasing, means for rotating the ring while said rotatable member is atrest, a vane member sealed to the shaft and projecting into the groove,and a conduit for conductingsealing liquid to the groove.

15. The combination with a turbine casing having an opening and arotatable shaft member horizontally disposed and projecting through theopening, of a rotary liquid sealing arrangement for sealing therotatable member to the casing during rotation of the rotatable memberas well as while said member is at rest, said arrangement comprising twoelements having portions concentric with the rotatable member, meanssecuring one of the elements to the rotatable member, and meansincluding a motor for rotating the other element, means to seal theother element to the casing, and means to supply sealing liquid to theother element.

ORLA L. woon- Ja,

